What role does the user@host that often appears at the end of a public ssh-rsa key play? Is it necessary? Does if serve any purpose in the authentication, or is it simply a record of who and where the key was created by for the information purposes (for a human reader)?

Thanks, that is exactly what I wanted to know. I assume the key is delimited from the comment with white space, and the keys are separated from each other with new lines?
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usedTobeaMemberMar 18 '14 at 13:35